Electric heater



Lugo im, @947, G, M. MARR ELECTRIC HEATER Filed 0G11. 22, 3.945

3 wuc/M/ofa e Mamie Patente-d Aug. 12, 1947 UNITED STATES PATENT OFFICE ELECTRIC HEATER George M. Marr, New York, N. Y.

Application (lctober 22, 1945, Serial No. 623,723

2` Claims. 1

This invention relates to improvements in electric heaters, wherein provision is made for heat distribution by convection, radiation and forced air circulation.

The objects of the invention are to provide a compact heater so arranged as to be safe in operation; to provide a heating unit of such type that if and when a wire of a heating coil should break or burn out, the coil will be retained in protected position, and thus avoid the free end contacting with the metal part of the heater and causing a short circuit; to provide a heater with several reflectors, each arranged to provide an airspace between a particular reflector and the heater housing; and nally to provide means for mounting the heater elements in suspension in the housing to permit contraction and explansion, destroying the elements.

In the drawings:

Figure 1 is a from'J elevation of the heater, parts being broken away to illustrate the interior structure; e

Figure 2 is a section on line 2-2 of Figure 1;

Figure 3 is a detail longitudinal section of the heater showing the end of the heating unit and connections;

Figure 4 is a detail cross section of th'e heating unit; and

Figure 5 is a diagrammatic view of the wiring.

Numeral I indicates a suitable housing, the front and rear walls at the bottom being cut out to form air inlet passages 2 and 3. The front wall of the housing near the top is formed with an opening 4, and in this opening is a grill 5. Secured inside the end walls of the housing are brackets 6, the upper end of each bracket being bent inwardly and downwardly as shown at 1, to provide end supports for one or more heating units.

The heating unit 8 consists of a non-conductor core 9, provided on its periphery with' a series of parallel grooves 9ar and a central rod I0, the ends of which extend beyond the core 9 and threaded as at Il. Heating coils I2 are seated in the grooves 9a, their ends being attached to end plates I3. The end plates are supported on the threaded ends of the rod and are clamped in position by nuts I4a. Below the heating unit one of the plates is provided with three clamping screws I4, I5 and I6, to secure wires for passage of current.

The downwardly bent ends of the brackets 6, are formed with openings to receive the threaded ends of the rod I IJ, the parts being retained in operative relation by the nuts Ma.

This arrangement supports the heating unit in suspension within the housing, and also allows for the contraction and expansion of the unit under heat conditions, when the heater is in operation.

Within the housing are three separate baies to insure maximum heating eifect wh'en the heatr is operated. The main reflector |60. extends frorn the top front of the housing above the grill and curves downwardly toward the rear wall of the housing to a point below the hori- Zontal plane of the heating unit. This reflector is transversely corrugated to insure reflection of any rays emanating from the heating unit.

It is to be noted that corrugated reflector IBa is spaced from the top, front and rear walls of the housing to provide an air space I1, to assist in maintaining th'e housing in as cool condition as possible.

A second reflector, indicate at I8, is mounted within the housing in front of and spaced from the heating unit and below the grill. This reflector I 8 extends entirely across the housing and is vertically inclined and spaced from the front of the housing. Thus an air space is provided for three circulation of convection currents and at the same time the front of the housing is isolated from direct radiant rays, which serves to maintain a low and safe temperature at th'e front of the housing.

As previously stated, the bottom of the front and rear walls of the housing are cut out to form air passages 2 and 3. Within and extending entirely across the housing mid-way of the lower air passages 2 and 3 is a reflector 2|. This particular reflector forms a dual purpose, namely, it acts to form passages for entry of air at the bottom of the housing and in addition prevents overheating by radiance and convection currents in the lower part of the housing.

Numeral 25 indicates a feed wire -connected to the heater unit. 26 indicates a wire connected at one end to a switch 3i] and its opposite end to one of the end plates I3. Another wire 3| is connected to the plate I3 and the opposite end to a switch 32. The wires 23 and 3| are connected with certain of the heating coils on the core so that by operating one switch a low heat will follow and if the opposite switch is turned to make contact, a second set of heating coils is electrically charged, thus a much greater heat from the heater unit is produced.

Brackets 35 are attached to one side of the housing over the switches to protect the latter and thus prevent accidental operation of the switches by one passing by the heater.

By operating the switches to make contact with the wires leading to the heating unit, the radiant glowing rays and convection currents are sent out in such manner as to utilize the heat effect in the most practical manner, When the unit is heated, air is drawn through the air passages 2 and 3 up and around the heating unit to the reflectors I8. The heated air passing upwardly around the unit is deflected by the re- I'iector |6a which increases the heat current toward reflector Ia. From this reflector the heat by radiation and convection is directed through the grill to the room.

Obviously, if one of the wires of the heating coils should break or burn out, it will be retained in the groove on the core. Hence, there is no chance of a short circuit if anything should happen to one of the heating coils.

The heating units is subjected to high temperature in view of which the unit is subjected to contraction and expansion, and unless provision is made to meet this contingency, serious damage to the unit follows. By mounting the unit in brackets capable of expanding or contracting, the unit is protected against damage by unusual or sudden lowering of temperature in the operation of the heater.

What I claim is:

l. In a heater having a housing provided with an outlet opening in its upper front wall and inlet openings adjacent the bottom, said housing having an electric heating element extending horizontally therein at a position below the bottom of the outlet, an upper reflector extending rearwardly and downwardly from the top part of the front wall to direct rising heat rays forwardly through the outlet, a second Ilat reflector mounted forwardly of the heating element in inclined position with its bottom in close proximity to the front wall and its top part spaced substantially inwardly thereof so as to reflect the heat rays from the heating element inwardly from the front Wall and toward the upper reilector, and a horizontally disposed reiiector in the bottom of said housing beneath said heater to reilect heat rays upwardly to said reflectors to be directed through said outlet.

2. In a heater having a housing provided with an outlet opening inV the upper part of its front wall and inlet openings in the bottom of its front and rear walls, an electric heating element mounted horizontally within said housing and substantially below said outlet opening, an upper reflector to direct heat rays forwardly, through said opening, said reilector extending rearwardly and outwardly from the top of the front wall to the rear wall at a point below said heating element, a second reflector mounted at an inclination forwardly of said heating element with its bottom adjacent to the forward wall below said heating element and its top spaced inwardly and terminating in a plane adjacent to the bottom edge of said outlet opening and substantially above said heating element so as to reflect the heat rays away from the front wall and toward the upper reector to be directed through said outlet opening, said reflectors tapering inwardly to deflect convection currents that are drawn in through said bottom openings into the vicinity of said heating elements, and a reector in the bottom of said housing below said inlet openings to reflect heat rays upwardly to said reflectors to be directed through said outlet opening.

GEORGE M. MARR.

REFERENCES CRTED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

